CDKN1A and gastric cancer: Cyclins and cyclin-dependent kinases (CDKs) are the two major proteins involved in cell cycle progression.200 Functional analysis revealed that Reprimo (RPRM) is transcriptionally regulated by p53 and serves to arrest the cell cycle at the G2/M checkpoint, by inhibiting nuclear translocation of the Cdc2/cyclin B1 complex.201 Significant downregulation of RPRM has been described in GC cells expressing wild-type p53.202 With DNA damage, the cell cycle is arrested in the G2/M phase as monitored by p53-mediated downregulation of p21, which prevents the transmission of mutagenic damage.200